Fig. 1. Schematic diagram of cylindrical liquid lens. (a) Initial uncharged liquid interface; (b) liquid interface at cross-section A-A when the applied voltage is U; (c) liquid interface at cross-section B-B when the applied voltage is U; (d) distribution of thin and thick dielectric layers in the conical hole surface

Fig. 2. Shapes of the liquid interface under different voltages, Y-Z, X-Z, and three-dimensional view. (a) 0 V; (b) 20 V; (c) 30 V; (d) 40 V

Fig. 3. Fit the liquid-liquid interface surface shapes under different voltages using a fifth-degree polynomial. (a) 35 V; (b) 40 V; (c) 45 V; (d) 50 V; (e) 55 V

Fig. 4. Shapes of the liquid interface under different voltages, with the edge regions neglected. (a) 35 V; (b) 40 V; (c) 45 V; (d) 50 V; (e) 55 V

Fig. 5. Fitting cross-sectional profiles of Y-Z plane under different voltages

Fig. 6. Ray aberration diagrams under different voltages. (a) 35 V; (b) 40 V; (c) 45 V; (d) 50 V; (e) 55 V

Fig. 7. Field curvature/distortion diagrams under different voltages, with a meridional incident field of view of 5°. (a) 35V; (b) 40 V; (c) 45 V; (d) 50 V; (e) 55 V

Fig. 8. Cylindrical liquid lens device and its zoom performance. (a) Completed liquid lens device; (b) relationship diagram between voltage and focal length

Fig. 9. Zemax simulation results. (a)‒(e) Graphs of lens focusing ability on parallel light at different voltages; (f)‒(j) simulation results of the spot on the detector plane

Fig. 10. Schematic diagram of zoom ability testing device

Fig. 11. Spot images corresponding at different voltages. (a) 55 V; (b) 50 V; (c) 45 V; (d) 40 V; (e) 35 V

Fig. 12. Comparison of the central width of simulated and experimental light spots when the detector is 139 mm away from the lens liquid-liquid interface

Fig. 13. Response time results for different driving voltages