1 × 4 optical switch based on electrowetting

Abstract

In this paper, we report a 1 × 4 optical switch using deformable liquid droplet. The deformation is produced by the electrowetting on dielectric phenomenon. The device consists of a dyed oil and a transparent conductive liquid sealed in a transparent cylinder. The top glass cover of the device has four independently addressable electrodes for the actuation of the liquid dome in each direction. In the voltage-off state, incident light is absorbed by the dyed liquid. When the voltage is applied to the liquid, the dome of the transparent liquid is uplifted and then spreads to four different directions because of the effect of electrostatic force. Accordingly, the transparent liquid pushes the dyed oil out to form a light path. The device with simple structure can freely control multiple switch apertures through changing the driven voltage. In addition, we analyze the electro-optical characteristics such as transmittance, response time (open time~110 ms, close time~160 ms), contrast ratio (~661:1).

Electric field effect on the contact angle for non-wetting drops

“…(8) Note that the equilibrium distance between the melt and dielectric slab is determined solely by the ratio of the Born and Hamaker constants. We have incorporated the term (H/ε + 1) into equation (7) and into the constant η. The electrowetting number η is the ratio of the electrostatic energy to the surface tension and is identical to the term that appears in the Lippmann equation (equation ( 1)).…”

“…This phenomenon is called electrowetting and it has received increased interest in recent years because of its potential uses in several applications. These have included microfluidics [1,2], liquid displays [3], manipulated wettability of quartz crystal balances [4], variable focus lenses for miniature cameras [5,6], optical switching [7,8], and energy harvesting [9,10]. Recent reviews have described the basics of electrowetting, static and dynamic aspects, and applications [11][12][13].…”