Low voltage driven microlens array based on ionic liquid doped polyvinyl chloride gels

Electrically responsive polyvinyl chloride (PVC) gels represent promising candidates for fabricating lenses with adjustable focal lengths. However, their practical use has been hampered by the elevated voltage requirements. In order to lower the driving voltage of PVC gels-based microlens array (MLA), trace ionic liquid (IL) −1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6) was doped. We employed a ring-array patterned electrode for the fabrication of PVC gel-based microlens arrays (MLAs). Our investigation revealed that the operating voltage for PVC gel-based MLAs doped with 0.01 wt% [BMIM]PF6 was nearly 1/22 of that required for MLAs created using undoped PVC gels. In the case of a microlens featuring a 250 μm aperture, the focal length varies from 4.2 mm to 2.5 mm as the voltage ranges from 5 V to 7 V. Importantly, this voltage range remains below the established safe limit for human exposure and obviates the need for intricate circuitry during manufacturing. Moreover, the extent of focal length variation can be expanded by augmenting the film thickness. Our approach offers valuable technical support for advancing the practical applications of PVC gel-based MLAs.