Koninklijke Philips Corporation N.v.

Jan Van De Kamer

Mark Thomas Johnson

Guofu Zhou

Rogier H M Cortie

Rogier Cortie

Alex V Henzen

Mischa Eduard Tanja Nelis

An image is updated on a bi-stable display () such as an electrophoretic display in successive frame periods by accessing data defining a set of voltage waveforms for the successive frame periods. At least a portion of the bi-stable display is driven during the successive frame periods according to the accessed data so that a longer frame period (FT,) is used during at least a first portion of the voltage waveforms, and a shorter frame period (FT') is used during at least a second portion of the voltage waveforms. For example, the longer frame period may be an elongated frame period, which is the longest period during which each of the voltage waveforms has a respective constant voltage value.

Driving method for an electrophoretic display with accurate greyscale and minimized average power consumption

Bi-stable electrophoretic display device () having a normal mode and a scrolling mode, in which image transitions are effected by causing the charged particles () to toggle between the intermediate optical states (e.g. grey-to-grey) or between an extreme optical state and an intermediate optical state (e.g. white-to-light grey), with a corresponding short update time t. When the device () enters a scrolling mode in response to a scrolling command from a user, picture elements are first driven to a special scrolling optical. state, after which drive waveforms for scrolling mode are used for fast toggling between two scrolling states. An increased scrolling speed and very short scrolling time can be realized, without adversely affecting image quality during a normal mode.

Scrolling function in an electrophoretic display device

An image is updated on a bi-stable display () such as an electrophoretic display by providing separate scaling functions (SF, SF) for scaling a duration of a reset pulse (R) and a duration of a driving pulse (D) in a drive waveform based on temperature (). An absolute value of a slope with varying temperatures of the scaling factor (SF) for the reset pulse (R) is significantly greater than that of the scaling factor (SF) for the driving pulse (D), while both scaling factors increase with decreasing temperature. Image update time (IUT) is significantly reduced at lower temperatures, while a range of variation of IUT across all temperatures is also reduced. Scaling functions (SF, SF) may also be used for scaling a duration of a help reset pulse (H) and/or a duration of one or more shaking pulses (SH, SH).

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Heerlen, Netherlands

Jan Van De Kamer