Electrowetting is a microfluidic phenomena that is currently enjoying explosive growth as a driving mechanism for a wide range of fluidic and electro-optic applications.
Electrowetting involves modifying the surface tension of liquids on a solid surface using a voltage. By applying a voltage, the wetting properties of a hydrophobic surface can be modified and the surface becomes increasingly hydrophilic (wettable).
With Electrowetting displays, the modification of the surface tension is used to obtain a simple optical switch by contracting a colored oil film electrically. Without a voltage, the colored oil forms a continuous film and the color is visible to the consumer. When a voltage is applied to the display pixel the oil is displaced and the pixel becomes transparent. When different pixels are independently activated, the display can show content like an photograph or a video.
We can also use this transmissive pixel as the basis for reflective of transflective displays.
Electrowetting in Action
The high switching speed (a few milliseconds) of electrowetting and its applicability to small (pixel) dimensions means that electrowetting is ideally suited for application to displays showing video content.