Abstract: An image is updated on a bi-stable display (310) such as an electrophoretic display in a transition from a current image state to a subsequent image state. A voltage waveform (600, 620, 640, 660; 700, 720, 740, 760) is selected based on the current and subsequent image states, and a previous image state. The bi-stable display (310) is driven from the current image state to the subsequent image state using the selected voltage waveform. For a given transition from the current to the next image state, different waveforms are stored for different previous states, e.g., black, dark grey, light grey and white. The different waveforms may have different drive pulse (DR) or reset pulse (RE1, RE2) energies. In a trial and error optimization process, different waveforms with different reset and/or drive pulse energies are tested for different previous image states to see which waveform yields the smallest greyscale error.

Abstract: An optical switch, e.g. a display device based on layer break up or layer displcement having at least two different states, in which one of the fluids (5) e.g oil in a first state adjoins at least a first support plate (3) and in the second state the other fluid (6) at least partly adjoins the first support plate, in which picture elements are separated by areas (13) having a hydrophilic surface.

Abstract: Display units (1) comprise display panels (90) which are divided into active parts and inactive parts. The driving of an entire display panel (90) requires a minimum amount of time, which amount of time increases with an increasing number of rows and columns. By providing data signals to the pixels (11) located in active parts, and by supplying reference signals simultaneously to pixels (11) located outside the active parts, most of an amount of time available in a frame period is used for the active part, and, for a given frame period, the number of rows and columns of the display panel (90) can be increased. Respective parts are made active during respective 3 periods. A part may comprise a group of columns (ADG, BEH, CFI) and/or a group of rows (ABC, DEF, GHI). The display panel (90) may comprise multiplexing circuitry (50) and/or shift register circuitry (60) to reduce the number of connections between the display panel (90) and the rest of the display unit (1).

Abstract: Several possibilities of driving devices (13,14,15) for optical switches, especially displays (1) based on the principle of electrowetting are given. This principle uses optical switches comprising a first fluid (5) and a second fluid (6) immiscible with each other within a space between a first transparent support plate (3) and a second support plate (4), the second fluid being electro˜conductive or polar.

Abstract: The present invention relates to a novel driving scheme for an electrophoretic display providing accurate intermediate optical states. According to the invention, the level of remnant voltage across pixels are taken into account when driving the display. Remnant voltage is built up when resetting the pixel between consecutive image states, and the reset states are therefore chosen so as to avoid the generation of excessive remnant voltage levels. The invention can for example be implemented using a counter, counting the number of consecutive uses of the same state as extreme state, or using a look-up-table in which driving history of the display is mapped and which determines the reset state to be used for the next reset based on the driving history. In effect, the threshold number of consecutive uses of the same state as a reset state is avoided.