Patent ID: 7786974

Claim:
A drive circuit ( 101 ) for driving a bi-stable matrix display device having a display screen ( 100 ) comprising a matrix of pixels ( 18 ), in a first display mode, the drive circuit ( 101 ) is arranged for generating during first image update periods (IUP 1 ) first drive voltage waveforms (DV 1 ) to allow a first set of optical states, and to supply the first drive voltage waveforms (DV 1 ) to a first subset of the pixels ( 18 ) covering a first area (W 1 ) of the display screen ( 100 ) only, in a second display mode, the drive circuit ( 101 ) is arranged for generating during second image update periods (IUP 2 ) second drive voltage waveforms (DV 2 ) to allow a second set of optical states, and to supply the second drive voltage waveforms (DV 2 ) to a second subset of the pixels covering a second area (W 2 ) of the display screen ( 100 ), wherein the optical states of the first set of optical states and of the second set of optical states are selected to obtain first image update periods (IUP 1 ) being shorter than the second image update periods (IUP 2 ).