Electrowetting element with ridge

An electrowetting element comprising a first fluid and a second fluid immiscible with the first fluid. A first support plate comprises: a first support plate surface in contact with at least one of the first fluid or the second fluid, a substrate having a substrate surface, an electrode and a ridge. The ridge comprises a substantially parallel ridge surface substantially parallel to the substrate surface and a sloping ridge surface angled relative to the substantially parallel ridge surface. A wall is located at least partly on the substantially parallel ridge surface. The ridge is configured to reduce a flow of the first fluid along an inner surface of the wall.