Electronically Responsive Adaptive Liquid Lens

Article: Researchers Use Electrically Responsive Fluid to Make Eye-Like Adaptive Lens
Source: Optica
Published: January 19, 2022

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Engineers in China are working on an adaptive liquid lens that changes its shape to change its focus, similar to the eye's natural crystalline lens. Made from a novel transparent electronically responsive liquid, dibutyl adipate (DBA), applying various input voltages produced a change in curvature to a model hemispherical plano-convex shape, specifically by movement of charge from cathode to anode in this electronegative material. The researchers state that the DBA exhibits high optical transmittance (95%), has good thermal stability (20–100°C), and can change its focal length from 7.5 mm to 13.1 mm with a change of voltage from 0 to 100 volts. DBA has a good imaging resolution of up to 29 lines per millimeter. They further highlight that DBA is lightweight, non-volatile, and inexpensive for application in phone cameras or eyeglasses without relying on mechanical elements, and could be a simpler alternative to existing adaptive lens technology based on electrowetting. Lead researcher of the project explains, "Our DBA liquid lens isn’t susceptible to volatilization or electrolysis, and because the DBA liquid directly contacts the electrode, there’s no need for an insulating layer. This gives the DBA lens a simpler structure and better stability compared to an electrowetting liquid lens." Meanwhile, the researchers continue to make improvements to the material's resolution, response speed, and weight.

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Xu M, Liu Y, Yuan Y, et al. "Variable-focus liquid lens based on electrically responsive fluid." Optics Letters.  43(3):509-512. 19 January 2022. https://doi.org/10.1364/OL.447182