JapaneseJournalofAppliedPhysics50(2011)037202REGULARPAPERDOI:10.1143/JJAP.50.037202LowVoltageElectrowettingOpticalDeflectorHsiu-HsiangChenandChien-ChungFuInstituteofNanoEngineeringandMicrosystems,DepartmentofPowerMechanicalEngineering,NationalTsing-HuaUniversity,Hsinchu300,Taiwan,R.O.C.ReceivedJuly12,2010;revisedNovember6,2010;acceptedDecember7,2010;publishedonlineMarch22,2011Thispaperdemonstratesalow-operating-voltageelectrowettingopticaldeflector(EOD)byreducingtheinterfacialsurfacetensionbetweentheelectrolyteandthesurroundingambience.Thegoalofthisstudywastoexplorevariousapproachestoachievingalowoperatingvoltage.First,twokindsoffluoropolymers(TeflonâAF1601andCytopâCTL-809M)wereutilizedtoconfirmthethicknesseffectandwettability.Second,threedifferentdielectriclayers(SiO2,Si3N4,andTa2O5)withthesamethicknessweretestedtoconfirmthedielectricconstanteffect.Finally,threedifferentsurfactants(sodiumdodecylsulfate(SDS),TritonX100,andTritonX15)wereusedtoconfirmtheinterfacialsurfacetensioneffect.Inthisâarticle,wedemonstratethatthecontactangleofwatercanchangeasmuchas70inadodecane/water/Cytop/Ta2O5system(containing1%SDS)with11V;furthermore,switchableapexanglesofÆ20anddeflectionofabeampassingthroughthemeniscusofEODarepresented.#2011TheJapanSocietyofAppliedPhysicsbiasbetweentheelectrolytedropletandtheelectrodetotune1.Introductioncontactangleofthedroplettoacertainrange.First,twoElectrowettingopticshasattractedmuchattentioninthelastkindsoffluoropolymers(TeflonÒAF1601andCytopÒCTL-decade.1,2)Intheelectrowettingphenomenon,changingthe809M)wereutilizedtoconfirmthethicknesseffectandpotentialdifferencebetweenanelectrolytedropletandwettability.Thehydrophobicitycharacteristicoffluoropo-electrodeisabletomanipulatethesurfaceenergyofthelymershelpedcreatealargerinitialcontactanglewhenelectrolytedropletand,asaconsequence,thecontactanglenobiasisapplied.Thefluoropolymerlayeralsoservedasofthedroplet.Thisphenomenonwasfirstexploitedbyadielectriclayer.Second,threedifferentdielectri