vai_a_storia   vai_a_organizzazione   vai_a_sedi   vai_a_personale   Area Riservata
    English English Version  

Tuneable liquid micro-lenses onto a functionalized polar dielectric substrates: formation and characterization

  Articoli su Riviste JCR/ISI  (anno 2010)

Autori:  Ferraro P., Grilli S., Paturzo M., Miccio L., Vespini V., Finizio A

Affiliazione Autori:  Istituto Nazionale di Ottica del CNR (INO-CNR) – Via Campi Flegrei, 34 Pozzuoli (NA) - Italy; Istituto di Cibernetica “E. Caianiello” del CNR – Via Campi Flegrei, 34 Pozzuoli (NA) - Italy

Riassunto:  Liquid lenses are becoming important optical devices for a wide range of applications, from mobile-phone cameras to biological imaging modalities. Their biggest advantage is their potential to have a variable focus that can be changed to obtain a different radius of curvature and thus optical power. The tunability of such micro-lenses could be of great interest to the field of micro-optics thanks to the possibility to achieve focus tuning without moving parts and thus favouring the miniaturization of the optical systems. A special class of tunable liquid micro-lenses is presented here. They are generated by electro-wetting effect under an electrode-less configuration. The lensing effect is induced by the pyroelectric effect on polar dielectric crystals we named pyroelectric-electrodeless-electro-wetting (PEEW). If a thin liquid film is spin coated on a z-cut lithium niobate wafer, the pyroelectric effect causes surface-charges at the liquid-solid interface when the substrate suffers temperature changes. Electric charges build up on the substrate\'s surface by pyroelectricity and are responsible for the variation of the liquid contact angle, thus forming liquid micro-lenses. The temperature variation can generate a pattern of electric charges onto the surface of the crystal when ferroelectric domain pattern is micro-engineered. Different types of lenses: spherical, cylindrical and toroidal have been formed. Any temperature change allows the liquid layer to become a tunable micro-lens array, showing a strong focusing effect. A digital holography technique is used to characterize the transmitted wavefront during focusing and focal length variation in the millimetre range is observed. Formation process is illustrated while interferometric characterization and imaging properties are analyzed and discussed.

Rivista/Giornale:  PROCEEDINGS OF SPIE
Volume n.:  7716      Pagine da: 77160C-1  a: 77160C-1
Ulteriori informazioni:  Su invito
DOI: 10.1117/12.858243

Riferimenti visionabili in IsiWeb of Knowledge: (solo per sottoscrittori)
Per visualizzare la scheda dell'articolo su IsiWeb: Clicca qui

INO © Istituto Nazionale di Ottica - Largo Fermi 6, 50125 Firenze | Tel. 05523081 Fax 0552337755 - P.IVA 02118311006     P.E.C.    Info