Methods for driving electro-optic displays

A method of driving an electro-optic display using a plurality of different drive schemes, the waveforms of the drive schemes being chosen such that the absolute value of the net impulse applied to a pixel for all homogeneous and heterogeneous irreducible loops divided by the number of transitions in the loop is less than about 20 percent of the characteristic impulse,

• wherein:
• a homogeneous irreducible loop is a sequence of gray levels, starting at a first gray level, passing through zero or more gray levels, and ending at the first gray level, wherein all transitions are effected using the same drive scheme, and wherein the loop does not visit any gray level except the first gray level more than once;
• a heterogeneous irreducible loop is a sequence of gray levels, starting at a first gray level, passing through one or more gray levels and ending at the first gray level, wherein the loop comprises transitions using at least two different drive schemes, the drive scheme used to effect the last transition in the loop is the same as the drive scheme used to effect the transition to the first gray level immediately prior to the start of the loop, and the loop comprises no shorter irreducible loops;
• and
• the characteristic impulse is the average of the absolute values of the impulses required to drive a pixel between its two extreme optical states.