Improvement of Varioptic's liquid lens based on electrowetting: how to obtain a short response time and its application in the design of a high resolution iris biometric system

Abstract

a Varioptic, a Business Unit of Parrot S.A., 24 B rue Jean Baldassini, 69007 Lyon (France); b Département d'optique théorique et appliquée, Unité haute résolution angulaire, ONERA, 29 AvABSTRACT This communication presents the results obtained for decreasing the response time of electrowetting-based real time focus correctors (liquid lenses).In order to provide a compact iris biometric system demonstrator, we have achieved a response time at 90% of 7.5 ms for a change in focalization from 0 diopter to 10 diopter with a liquid lens having an aperture of 1.9 mm. We have used a hydrodynamic fluid reorganization model to predict the features of these fast liquid lenses and evaluated the sensivity of the response time to the different conception parameters.

Three dimensional two-photon brain imaging in freely moving mice using a miniature fiber coupled microscope with active axial-scanning

“…We demonstrated more complex 3D scans with tilted field imaging, which may be important for accessing features that are not confined to a single focal plane. In this study we altered the EWTL FL slowly through the scan, but the EWTL has been shown to be capable of varying the FL at ~50 Hz or greater when driven at resonance 37 , 38 . In the future we can implement more efficient driving functions for the EWTL to achieve high-speed axial scanning, opening the potential for random-access scanning for truly volumetric data collection 3 , 4 , 39 .…”

Three dimensional two-photon imaging of neuronal activity in freely moving mice using a miniature fiber coupled microscope with active axial-scanning

“…We demonstrated more complex 3D scans with tilted field imaging, which may be important for accessing features that are not confined to a single focal plane. In this study we altered the EWTL FL slowly through the scan, but the EWTL has been shown to be capable of varying the FL ∼50 Hz or greater when driven at resonance 37,38 . In the future we can implement more efficient driving functions for the EWTL to achieve high-speed axial scanning, opening the potential for random-access scanning for truly volumetric data collection 3,4,39 .…”

Tunable Liquid Lenses: Emerging Technologies and Future Perspectives

“…The low liquid viscosity and interfacial tension can reduce the response time of the lens. [67] In addition, Supekar et al studied the relationship between the response time and the input voltage and obtained the best shape of driving voltage with the fastest response time. It was shown that the response time was decreased by 29% with two exponential input voltages.…”