Patent ID: 8279166

Claim:
A display apparatus comprising: a plurality of electrofluidic chromatophore (EFC) pixel cells, each pixel cell comprising: i) a fluid holder for holding a polar fluid and a non-polar fluid having differing display properties, the fluid holder comprising: (1) a fluid reservoir with a geometry having a small visible area onto the polar fluid, and (2) a channel with a geometry having a large visible area onto the polar fluid, the channel being connected to the reservoir so as to enable free movement of the polar fluid and non-polar fluid between the channel and the reservoir, at least part of a surface of the channel comprising a wetting property responsive to a supply voltage, and ii) at least two pixel cell terminals arranged to provide the supply voltage to the at least part of the surface of the channel comprising the wetting property; a circuit board, the circuit board comprising: i) a plurality of switching circuits for supplying a switched voltage to the pixel cells, the plurality of switching circuits each being connected to at least one of the pixel cell terminals, ii) a plurality of row and column electrodes, the row and column electrodes being pairwise coupled to the switching circuit, and iii) a driver configured to charge the row and column electrodes and activate the switching circuits to address the switched voltage to the pixel cell, so as to generate the supply voltage resulting in a movement of the polar fluid to change a cell display property; wherein the pixel cell comprises at least one further pixel cell terminal that is coupled to a further electrode to supply a direct voltage to the pixel cell; wherein the driver is further configured to additionally charge the further electrode, to define a pixel cell intermediate condition; wherein the driver is configured to supply a direct voltage to the pixel cell that is dependent on the cell display property change; and wherein the driver is configured to provide the direct voltage, and a substantially minimal switched voltage, the direct voltage resulting in a basic supply voltage that minimizes an electromechanical force in the channel, and wherein the driver is configured to supply a switched voltage resulting in an increased electromechanical force that moves the polar fluid into the channel.