Miniaturized variable-focus lens fabrication using liquid filling technique

This paper describes a simple method for fabricating a variable-focus lens using polydimethylsiloxane (PDMS) filling with liquid to produce a variable-focus lens. A 2-mm diameter lens was designed in this experiment, expected to reach a focal length in the range of 3 ∼ 12 mm. The theoretical value between the liquid volume and the lens contact angle at different focal lengths were simulated and measured. The pumped-in liquid volumes ranged from 200 to 1,400 μl. The contact angles ranged from 14.25° to 49.02°. Variable focal length was produced by changing the PDMS film deformation using different micro-fluidic volumes. The focal length produce in the experiment was from 4 ∼ 10 mm. The proposed method successfully fabricated a variable-focus lens. Bonding PDMS only once using no expensive instrument such as oxygen plasma was accomplished. The final objective is to insert the variable focus lens into portable optical imagery products.