Passive Matrix Electrophoretic Display with Reset

An electrophoretic display device (1) comprising an electrophoretic material comprising charged particles (6) in a fluid (5), a plurality of sets of picture elements (2), first and second electrodes (3,4) associated with each picture element (2), the charged particles (6) being able to occupy a position being one of a plurality of positions between said electrodes (3,4), said positions corresponding to respective optical states including at least first and second extreme optical states, the device further comprising drive means arranged to supply a sequence of drive signals (D) to said electrodes (3,4), each drive signal (D) causing said particles (6) to occupy a predetermined optical state corresponding to image information to be displayed, and select means for applying a select signal (S) to a set of picture elements (2) to which said drive signals (D) are to be applied, wherein, in order to update an image displayed on said device (1), said select means is further arranged to apply a reset signal (Rn) to one or more of said sets of picture elements (2) prior to applying a respective select signal (S) thereto, each reset signal (Rn) causing said particles (6) to occupy one of said extreme optical states.

A method of driving an electrophoretic display device (1) comprising an electrophoretic material comprising charged particles (6) in a fluid (5) a plurality of sets of picture elements (2), first and second electrodes (3,4) associated with each picture element (2), the charged particles (6) being able to occupy a position being one of a plurality of positions between said electrodes (3,4), said positions corresponding to respective optical states including at least first and second extreme optical states, the method comprising supplying a sequence of drive signals (D) to said electrodes (3,4), each drive signal (D) causing said particles (6) to occupy a predetermined optical state corresponding to image information to be displayed, the method further comprising updating an image displayed on said device (1) by:

• (a) substantially simultaneously applying a reset signal (R1) to each of a plurality of said sets of picture elements (2), each reset signal (R1) causing said particles (6) to occupy one of said extreme optical states;
• (b) sequentially selecting one or more picture elements (2) of said sets of picture elements (2) to which a reset signal (R1) has been applied, and applying thereto a drive signal (D).

A method of driving an electrophoretic display device (1) comprising an electrophoretic material comprising charged particles (6) in a fluid (5), a plurality of sets of picture elements (2), first and second electrodes (3,4) associated with each picture element (2), the charged particles (6) being able to occupy a position being one of a plurality of positions between said electrodes (3,4), said positions corresponding to respective optical states including at least first and second extreme optical states, the method comprising supplying a sequence of drive signals (D) to said electrodes (3,4), each drive signal (D) causing said particles (6) to occupy a predetermined optical state corresponding to image information to be displayed, and applying a select waveform including a select signal (S) to a set of picture elements (2) to which said drive signals (D) are to be applied, wherein, said select waveform further includes a reset signal (Rn) to be applied to one or more of said sets of picture elements (2) prior to applying a respective select signal (S) thereto, each reset signal (Rn) causing said particles (6) to occupy one of said extreme optical states.