Activation and control of microlens liquid arrays on functionalized polar electric crystal substrates by electro-wetting effect and temperature

In recent years a variety of liquid bases optical elements have been conceived, designed and fabricated even for commercial products like digital cameras o cellular phone cameras. The impressive development of microfluidic systems in conjunction with optics has led to the creation of a completely new Science field of investigation named optofludics. Optofludics, among others topics, deals with investigation and methods for realizing liquid micro-lenses. A variety of liquid micro-lenses have been designed and realized by using different configurations. We demonstrate that a lensing effect can be obtained in an open microfluidic system by using a thin layer of liquid on a polar electric crystal such as Lithium Niobate (LiNbO3). Electrowetting patterning on LiNbO3 surface is obtained by pyroelectric effect consisting in a simple but reliable electrodes-less and circuit-less configuration. The electrodes are intrinsically embedded into the substrate. The material is functionalised by means of a micro-engineering electric filed poling process. Lens array with variable focus has been demonstrated with a large number of lens elements (10x10) on micrometric scale (aperture of single lens 100 microns).

[1]  G. Rosenman,et al.  Electron emission from ferroelectrics , 2000 .

[2]  J P Carrico,et al.  Thermally stimulated field emission from pyroelectric LiNbO3 , 1974 .

[3]  Hans Riegler,et al.  Reversible self-propelled droplet movement: a new driving mechanism. , 2005, Physical review letters.

[4]  S. Herminghaus,et al.  Electrostatic stabilization of fluid microstructures , 2002 .

[5]  Sandra M. Troian,et al.  Patterning liquid flow on the microscopic scale , 1999, Nature.

[6]  Reinhard Lipowsky,et al.  Wetting morphologies at microstructured surfaces. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[7]  Shah,et al.  Electrochemical principles for active control of liquids on submillimeter scales , 1999, Science.

[8]  A. K. Agarwal,et al.  Adaptive liquid microlenses activated by stimuli-responsive hydrogels , 2006, Nature.

[9]  Duncan Graham-Rowe,et al.  Liquid lenses make a splash , 2006 .

[10]  Ashutosh Sharma,et al.  PATTERN FORMATION IN UNSTABLE THIN LIQUID FILMS , 1998 .

[11]  Alexei A Kornyshev,et al.  Electrowetting with electrolytes. , 2006, Physical review letters.

[12]  Shin‐Tson Wu,et al.  Tunable-focus liquid lens controlled using a servo motor. , 2006, Optics express.

[13]  Seth R. Marder,et al.  Local wettability modification by thermochemical nanolithography with write-read-overwrite capability , 2007 .

[14]  Pietro Ferraro.  What breaks the shadow of the tube , 1998 .

[15]  S. Kuiper,et al.  Variable-focus liquid lens for miniature cameras , 2004 .

[16]  G. Beni,et al.  Dynamics of electrowetting displays , 1981 .

[17]  Mwj Menno Prins,et al.  Fluid control in multichannel structures by electrocapillary pressure. , 2001, Science.

[18]  Peter Malcolm Moran,et al.  Fluidic lenses with variable focal length , 2006 .

[19]  S. Cho,et al.  Low voltage electrowetting-on-dielectric , 2002 .

[20]  Gil Rosenman,et al.  Wettability patterning of hydroxyapatite nanobioceramics induced by surface potential modification , 2006 .

[21]  Ed Colgate,et al.  An investigation of electrowetting‐based microactuation , 1990 .

[22]  B. J. Feenstra,et al.  Video-speed electronic paper based on electrowetting , 2003, Nature.

[23]  J. Baret,et al.  Electrowetting: from basics to applications , 2005 .

[24]  J. Yeh,et al.  Dielectrically actuated liquid lens. , 2007, Optics express.

[25]  T. Gaylord,et al.  Lithium niobate: Summary of physical properties and crystal structure , 1985 .