Fig. 1. Schematic cross-sectional structure and operating mechanism of the movable electrowetting optofluidic lens.(a) Cell structure. The curvature of the silicone oil (yellow)-conductive liquid (blue) interface in the central aperture is regulated by the external voltages. (b) Moving actuation. When the external voltages U₁ and U₃ are applied, the L-L interface moves downwards. (c) Deforming actuation. When external voltage U₂ and U₄ are applied, the L-L interface deforms. (d) Working principle of axial scanning.

Fig. 2. Performance of moving and deforming actuation of the movable electrowetting optofluidic lens.(a) Cell structure. (b) State 1, U_A= 0 V, U_B=0 V. (c) State 2, U_A=50 V, U_B=0 V. (d) State 3, U_A=50 V, U_B=60 V, t=0 s. (e) State 3, U_A=50 V, U_B=60 V, t=1 s. (f) Shift distance with different voltages.

Fig. 3. Fabricated prototype of the movable electrowetting optofluidic lens.(a) All the elements of the device. (b) Assembled prototype (Side view). (c) Assembled prototype (Top view).

Fig. 4. (a) Simulation of the movable electrowetting optofluidic lens. (b) MTF for 20 mm object distance. (c) MTF for 20.5 mm object distance. (d) MTF for 21 mm object distance.

Fig. 5. Imaging experiment using the movable electrowetting optofluidic lens.(a) Experiment setup. (b) Specimen A. (c) Specimen B. (d) Specimen A and B stacked together. (e) Focusing on specimen A. (f) Focusing on specimen B.