Addressing multistable nematic liquid crystal device
AssigneeZBD Displays Limited
InventorJohn C Jones
Life of this patent
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Abstract
A method of addressing multistable nematic liquid crystal devices, in particular bistable nematic liquid crystal devices is provided. The method is a line at a time addressing scheme where one of at least two data waveforms is applied simultaneously to each of the column electrodes whilst a strobe waveform is applied to a row. The strobe waveform comprises a blanking portion sufficient to cause the liquid crystal material to blank, irrespective of which data waveform is applied, immediately followed by a discriminating portion which is such that in combination with an appropriate data waveform allows for selective latching. At least part of both the blanking portion and the discriminating portion are applied during the line address time for the particular row of interest.
Claims17
A method for addressing a multistable nematic liquid crystal device having a layer of nematic liquid crystal material disposed between two cell walls and row and column electrodes disposed on the cell walls to form an addressable matrix of pixels, and having a cell wall surface treatment such that the liquid crystal material is latchable between at least two stable molecular configurations upon application of appropriate voltage pulses comprising the steps of applying a strobe waveform to each row electrode in a sequence and applying one of at least two data waveforms, to each column electrode simultaneously wherein each data waveform has a duration equal to the line address time and has a zero net dc value and wherein the strobe waveform has a net zero dc value over a whole frame time and comprises a blanking portion which in combination with any data waveform will cause the liquid crystal material to adopt a first particular state immediately preceding a discriminating portion which in combination with one data waveform will cause the liquid crystal material to remain in the first stable state and in combination with another data waveform to latch to the another stable state, characterised in that only one strobe waveform is applied to each row when addressing a particular frame and in that during the line address time wherein the appropriate data waveform is applied to each column for the pixels of a particular row at least part of the blanking portion and at least part of the discriminating portion is applied to that row.
A multistable nematic liquid crystal device comprising a layer of nematic liquid crystal material disposed between two cell walls, at least one cell wall having a surface treatment such that the liquid crystal material is latchable between at least two stable molecular configurations upon application of appropriate voltage pulses, row and column electrodes disposed on the cell walls to form an addressable matrix of pixels, and driving means for applying a strobe waveform to each row electrode in a sequence and one of at least two data waveforms, to each column electrode simultaneously wherein each data waveform has a duration equal to the line address time and has a zero net dc value and wherein the strobe waveform has a net zero dc value over a whole frame time and comprises a blanking portion, which in combination with any data waveform will cause the liquid crystal material to adapt a first particular state, immediately preceding a discriminating portion, which in combination with one data waveform will cause the liquid crystal material to remain in the first stable state and in combination with the another data waveform to latch to the another stable state, characterised in that the driving means is adapted such that only one strobe waveform is applied to each row when addressing a particular frame and in that during the line address time wherein the appropriate data waveform is applied to each column for the pixels of a particular row at least part of the blanking portion and at least part of the discriminating portion is applied to that row.
Dependencies are inferred from the claim text.