Patent ID: 8508468

Claim:
A display apparatus, the 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) a fluid reservoir with a geometry having a small visible area projected in the direction of the viewer, and (b) a channel with a geometry having a large visible area projected in the direction of the viewer, the channel being connected to the reservoir so as to enable 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, at least two pixel cell terminals being arranged to provide the supply voltage to the at least part of the surface of the channel comprising the wetting property; the supply voltage resulting in a movement of the polar fluid to change a cell display property or in the absence of movement of the polar fluid being a stable voltage; a circuit board, the circuit board comprising: a switching circuit for supplying an electrical charge to the pixel cells, the switching circuit being connected to one of the at least two pixel cell terminals, so as to generate the supply voltage, a row and column electrode coupled to the switching circuit; and a driver configured to charge the row and column electrodes and activate the switching circuits; and a display controller arranged to control the driver as a result of pixel image information inputted in the display controller; the display controller comprising a state lookup table storing, for a respective pixel cell, the current pixel cell display property, the display controller further arranged to calculate the electrical charge as a function of the current pixel cell display property and the a new pixel cell display property; and wherein controller controls the driver to supply the calculated electrical charge to the pixel cell, wherein: the driver is arranged to supply the calculated electrical charge to the pixel cell by providing a switched voltage, the switched voltage resulting in a supply voltage different from the stable voltage; and the switched voltage is provided based on a ratio of a first calculated pixel capacitance to a second calculated pixel capacitance, the first calculated pixel capacitance corresponding to the new pixel cell display property and the second calculated pixel capacitance corresponding to the current pixel cell display property.