Method of driving a matrix type phase transition liquid crystal display device to obtain a holding effect and improved response time for the erasing operation

Claim 1

An amplitude selective multiplexing method of driving a matrix type liquid crystal display device which includes a layer of guest-host type phase transition liquid crystal sandwiched between a pair of electrode groups including at least one transparent electrode group and arranged in the form of a matrix, intersecting portions of said electrode groups being employed as display segments for displaying information by driving column or row electrodes of said matrix electrode groups with a one-line-at-a-time scanning system, wherein said phase transition liquid crystal exhibits a hysteresis characteristic in the relative brightness thereof against root mean square values of applied voltage, said amplitude selective multiplexing matrix driving method comprising: scanning said segments and applying across them a write-in voltage when the segments are to be changed from an off state to an on state, an erasing voltage when the segments are to be changed from the on state to the off state, and a holding voltage when a present on or off state of each of the segments is to be maintained; and applying a holding voltage across each of segments other than segments just subjected to scanning to maintain the present on or off state of the segments, wherein said write-in voltage has a root mean square value sufficient for effecting such a phase transition of said phase transition liquid crystal from a low brightness to a high brightness condition thereby to turn on said display device, said holding voltage has a root mean square value lower than said write-in voltage and not sufficient for effecting the phase transition of said phase transition liquid crystal thereby to hold the present brightness of said display device at the level it is at at the moment the holding voltage is applied, and said erasing voltage has a root mean square value lower than said holding voltage and sufficient for effecting such a phase transition of said phase transition liquid crystals from the high brightness to the low brightness condition thereby to turn off said display devices.