Soft lens with large focal length tuning range based on stacked PVC gel actuators

Herein, a novel tunable lens with large focal length change and driven by stacked PVC gel actuators, is designed and characterized. The lens rigid parts are 3D-printed and commercially available while the PVC gel membrane is in volume production. Under electrical actuation, the lens attains focal length ranging from 30 to 217 mm within 400 V. A manual regulating mechanism is proposed for the finished lens which dexterously adjusts the initial focus and focal length range. Under compound actuation mode, large focus variation over 950% is achieved within 250 V. Under 250 V step input, the lens shows practical response time around 291 ms. Focal length tuning ability of the lens is also demonstrated by capturing images of objects placed in different positions. This tunable lens is promising for various smart optics.