Abstract
We have fabricated a fully-flexible, focus-tunable microlens array on a sheet and demonstrated its imaging capabilities. Each liquid lens of the array is individually tunable via electrowetting on dielectric (EWOD) actuation and is situated on a polydimethylsiloxane (PDMS) substrate, which allows the lens array to operate as a reconfigurable optical system. In particular, we observed a significant increase in the field of view (FOV) of the system to 40.4° by wrapping it on a cylindrical surface as compared to the FOV of 21.5° obtained by the array on a planer surface. We also characterized the liquid lenses of the system, observing a range of focus length from 20.2 mm to 9.2 mm as increased voltage was applied to each EWOD lens. A Shack–Hartmann wavefront sensor (SHWS) was used to measure the wavefront of the lens as it was actuated, and the aberrations of the lens were assessed by reporting the Zernike coefficients of the wavefronts.
Highlights
Liquid microlenses have been well established as viable solutions to enable tunable focal lengths for imaging, leading to increases in versatility of miniature imaging systems
There are a number of possible sources of aberrations that lead to this decrease in resolution, among which is the tendency of liquid lenses to exhibit spherical aberration, as discussed earlier, and the possibility of contamination of the electrowetting surface by dust particles, which can lead to small asymmetries in lens actuation
We have detailed a successful fabrication method for constructing a 5 × 5 array of independently tunable, electrowetting on dielectric (EWOD) microlenses on a flexible sheet. This method improved on previous designs by changing materials to allow for a more stable hydrophobic/hydrophilic boundary necessary to define the rest state of the lens, and by reducing the thickness of the dielectric layer, which allowed for increased amount of actuation at applied voltages
Summary
Liquid microlenses have been well established as viable solutions to enable tunable focal lengths for imaging, leading to increases in versatility of miniature imaging systems. Tunable lenses operate by either changing the refractive index of the lens or by changing its curvature in order to induce a change in the focal length. They usually utilize two liquids of different indices of refraction, the curved interface between them defining the lens. By seeking to create an array of electrowetting lenses on a flexible substrate we endeavor to achieve a highly reconfigurable imaging platform for visible wavelengths, capable of providing a wideBfyielsdeeokfivnigewto(FcrOeVat)ewahneanrwraryapopf eedleoctnroawcoenttvinegx sluenrfsaecse.oTnhaisflisexdiobnlee sbuybssttirtcahteinwgetheenidnedaiviodrutaol aimchaiegvees farohmighthlyerleecnosnefis ginurthabelaerirmayagtoinggetphleartfionrtmo afosrinvgisleibilme wagaev,ealnendgtthhes,ecxatepnatbolef othf eprinocvriedainsegianwFOidVe fiweilldl obfevdieewter(mFOinVe)dwbhyenthwerarapdpieuds oonf acucorvnavteuxrseuorfatchee. CAodmdbitinioantiaolnlyw, witrhatphpeinugnothbetrfulesixvibelfeosrumbfsatrcatoter onf tahecomniccarvoelesnusrafarcraeywcoouulldd ehnaavbelepathrteicaurlraarylytoreallesvoabnet auptiplilziceadtifoonrs3iDn imaging.fIonr omrodneritotoriancghoiervseutrhveeihlliagnhcyeipeludrpreoqsuesir. eAddtdoimtioankaelluys, eworfapanpianrgratyheinflwexhibiclhe stuhebsetnratitreeoanrraaycoisncfaabvreicsautrefdacteogweothueldr aenndabinledtivhiedaurarlacyotmo palosnoebnetsuctailnizneodt bfoere3xDchiamnaggeidn,gw. eInmoarderutsoe aocfhaienvaertehael hdiegnhsiytiyelmd oredquulairteeddteolemctarkoeduesdeeosfigan athrraatywine wprheivcihouthselyenretipreoratrerday[1is5]f,awbrhicicahtedsimtopgelitfhieedr athnedfianbdriivciadtuioanl cpormocpeosnseanntds ciamnpnrootvbeedeyxciehladn.ged, we made use of an areal density modulated electrode design that we previously reported [15], which simplified the fabrication process and improved yield
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
