Ultrasonic high-speed variable-focus optical lens

A high-speed variable-focus liquid optical lens using acoustic radiation force is proposed. The lens consists of a piezoelectric ring and a lens cell filled with degassed water and silicone oil. The profile of the oil-water interface can be rapidly varied by applying acoustic radiation force from the ultrasonic transducer, allowing the liquid lens to be operated as a variable-focus lens. The fastest response time of 6.7 ms was obtained with silicone oil with a kinematic viscosity of 100 cSt. The lens could scan at focal lengths of from 7.0 to 14.5 mm at 1 kHz in the axial direction.