Patent ID: 7796115

Claim:
An electrophoretic display device ( 1 ) comprising; an electrophoretic material comprising charged particles ( 8 , 9 ) in a fluid ( 10 ), a plurality of picture elements, first and second electrodes ( 5 , 6 ) associated with each picture element, the charged particles ( 8 , 9 ) being able to occupy a position being one of a plurality of positions between said electrodes ( 5 , 6 ), said positions corresponding to respective optical states including at least first and second extreme optical states and at least one intermediate optical state, the device ( 1 ) further comprising; drive means arranged to supply a drive waveform to said electrodes ( 5 , 6 ) said drive waveform comprising a sequence of drive voltage pulses corresponding to image data signals ( 102 ) for effecting image transitions by causing said particles ( 8 , 9 ) to occupy respective predetermined optical states corresponding to image information to be displayed, said device ( 1 ) being arranged to enable a user to effect scrolling of displayed image information by generating a scrolling command, in response to which charged particles ( 8 , 9 ) occupying positions in a first extreme optical state are caused to occupy a first intermediate optical state and charged particles ( 8 , 9 ) occupying a second extreme optical state are caused to occupy a second intermediate optical state, wherein said first and said second intermediate optical states are those closest to a corresponding one of said first extreme and said second extreme optical states.