Patent ID: 8599465

Claim:
A method for making an electrowetting device, comprising: providing a substrate including a conductive layer and an insulating layer disposed on the conductive layer; forming a light-impermeable layer on the insulating layer; patterning the light-impermeable layer to form a surrounding wall and a primary microchamber which is defined by an inner peripheral surface of the surrounding wall and which extends from a top surface of the light-impermeable layer to terminate at and expose an upper surface region of the insulating layer; applying a hydrophobic coating material to the upper surface region of the insulating layer to form a bottom region, to the inner peripheral surface of the surrounding wall to form a surrounding region, and to the top surface of the light-impermeable layer; removing the hydrophobic coating material applied to the top surface of the light-impermeable layer, while leaving the bottom region and the surrounding region intact, thereby providing the primary microchamber with a hydrophobic coating layer; and filling the primary microchamber with a liquid which includes a first solution and a second solution that is immiscible with the first solution, such that once a voltage is applied between the second solution and the conductive layer, the liquid transforms from a first state, in which the first solution lies below the second solution so as to permit the first solution to fully cover the bottom region, to a second state in which the first solution partially covers the bottom region of the hydrophobic coating layer so as to permit the second solution to come into contact with the bottom region.