A novel configuration of variable-focus liquid lens based on an electrowetting-on-dielectric technique is presented

which consists of a glass slide coated with a conductive Indium Tin Oxide (ITO) film

a hydrophobic dielectric film

a hollow conical metal ring suspended right above a gap between the slide and the ring

and the lens liquid (water). By changing the voltage applied to a grounded metal ring and a ITO control electrode

both the position and curvature of the liquid meniscus can be reversibly adjusted

and the focal length of the lens can be tuned. The shapes of the suspended ring in the present work are also designed to self-center the lens liquid

then influences of different shapes of the suspended rings on the variation of optical power of the meniscus are discussed. Experimental results show that the liquid lens at a good imaging quality is able to focus on objects away from 2.5 cm up to infinity at a 40 V power supply and also able to offer the variation range of the optical power up to 40 m

-1

. Because of the properties such as low consumption

small sizes and high reversibility and so on

the demonstrated configuration provides great advantages in the field of microlens.