Patent ID: 8547325

Claim:
A display apparatus comprising: a plurality of electrofluidic chromatophore (EFC) pixel cells, each pixel cell comprising: a fluid holder for holding a polar fluid and a non-polar fluid having differing display properties, the fluid holder comprising: a reservoir with a geometry having a first visible area projected in the direction of a viewer onto the polar fluid, and a channel with a geometry having a second visible area projected in the direction of a viewer 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 over the pixel cell, and at least two pixel cell terminals configured to provide the supply voltage to at least part of the surface of the channel comprising the wetting property; a circuit board comprising: a switching circuit connected to a switched terminal of the pixel cell for supplying a switched voltage to the pixel cells, a row electrode connected to the switching circuit, a column electrode connected to the switching circuit, and a driver configured to provide a drive signal charging the row electrode and the column electrode to activate the switching circuit to address the switched voltage to the pixel cell; and wherein the first visible area is smaller than the second visible area, and the display apparatus further comprises a display controller for controlling the driver, the display controller configured to execute the steps of: determining still-image pixels displaying still-image content wherein the present cell display properties of the pixels remain substantially identical, providing still-image drive signals to the still-image pixels, addressing a still image voltage to the at least one other pixel cell terminal other than the switched terminal of the still-image pixels, resulting in a stable supply voltage that stabilizes the cell display properties of the still-image pixels so as to display still-image content in an energy efficient manner, and providing moving-image drive signals by the driver to apply to the moving-image pixels that do not remain substantially constant, wherein the moving-image drive signals address a direct voltage differing from the still image voltage, to the another one of the at least two pixel cell terminals, the display controller comprising a mode switch to switch between the moving-image drive signals and the still-image drive signals dependent on the image content.