Patent ID: 6268840
Filing Date: 2001-07-31
Classification: G09G

Abstract:
A method of activating a bistable cholesteric liquid crystal material disposed between a first set of electrodes and a second set of electrodes arranged on opposed sides of said liquid crystal material that are adapted to selectively apply an electric field through said liquid crystal material, said method comprising the steps of:a) energizing said electrodes to establish a preparation voltage across said liquid crystal during a preparation interval, thereafter energizing said electrodes to establish a bipolar selection voltage across said liquid crystal during a selection interval for selecting a final display state for said liquid crystal; thereafter energizing said electrodes to establish an evolution voltage across said liquid crystal during an evolution interval, and thereafter permitting said liquid crystal to exhibit its final display state during a holding interval; andb) said step of energizing during the selection interval accomplished by combining a first unipolar voltage waveform coupled to at least one electrode of the first set of electrodes and a second unipolar voltage waveform coupled to at least one electrode of the second set of electrodes to apply the bipolar selection voltage across the liquid crystal material.