Addressing liquid crystal cells using bipolar data strobe pulses
AssigneeStc PLC
InventorsPeter J. Ayliffe, Anthony B. Davey, Johannes K. Zelisse
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Abstract
A method of addressing a matrix addressed ferroelectric liquid crystal cell is described that uses parallel entry of balanced bipolar data pulses on one set of electrodes to co-operate with serial entry of unipolar strobe pulses on the other set of electrodes. Data entry is preceded with blanking (erasing) pulses applied to the strobe lines. The polarity of the strobing and blanking pulses is periodically reversed to maintain charge balance in the long term.
Claims12
A method of addressing a matrix-array type liquid crystal cell with a ferroelectric liquid crystal layer whose pixels are defined by the areas of overlap between the members of a first set of electrodes on one side of the liquid crystal layer and the members of a second set on the other side of the layer, each such pixel being capable of being switched between first and second states respectively by the co-operation of a strobe pulse with a data pulse of a first data significance and by the co-operation of a strobe pulse with a data pulse of a second data significance, in which method
- (a) the cell is addressed on a line-by-line basis by applying strobe pulses serially to the members of said first set of electrodes while data pulses are applied in parallel to the members of said second set of electrodes,
- (b) the waveforms of said strobe and data pulses are both balanced and bipolar, and
- (c) the addressing of any given pixel includes a zero voltage portion within each said bipolar strobe pulse.
Dependencies are inferred from the claim text.