Multiplex addressing of ferro-electric liquid crystal displays

A method of multiplex addressing a ferroelectric liquid crystal matrix display comprising a layer of liquid crystal material contained between two cell walls carrying electrodes formed as a first set of electrodes on one cell wall and a second set of electrodes on the other cell wall, the electrodes comprising a matrix of addressable intersections, at least one of the cell walls being surface treated to provide surface alignment to liquid crystal molecules along a single direction, said method comprising the steps of:

• generating for each electrode in the first set of electrodes a first waveform comprising a pulse of one polarity and a pulse of opposite polarity, at least one of said pulses comprising a non-blanking strobe waveform wherein a blanking waveform is one in which all pixels along an electrode in the first set of electrodes are switched to a first display state irrespective of a data waveform applied to the electrodes in the second set of electrodes, said strobe waveform comprising a first pulse having a duration of ts and a voltage level, said first pulse immediately followed by a second pulse having a duration greater than ts and a voltage level of greater amplitude than the voltage level of the first pulse;
• generating two data waveforms of alternating positive and negative value pulses with one data waveform pulse the inverse of the other data waveform pulse, each data waveform pulse having a duration ts;
• applying said strobe waveform separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes;
• applying one of said two data waveforms for a time period of 2ts to each electrode in the second set of electrodes synchronized with the start of the strobe waveform applied to each electrode in the first set of electrodes, whereby each intersection is addressed with the resultant of said strobe waveform and appropriate data waveform to turn selected intersections to a desired display state once per complete display address period.

A method of multiplex addressing a ferroelectric liquid crystal matrix display comprising a layer of liquid crystal material contained between two cell walls carrying electrodes formed as a first set of electrodes on one cell wall and a second set of electrodes on the other cell wall, the electrodes comprising a matrix of addressable intersections, at least one of the cell walls being surface treated to provide surface alignment to liquid crystal molecules along a single direction, said method comprising the steps of:

• generating for each electrode in the first set of electrodes two non-blanking strobe waveforms of opposite polarity, wherein a blanking waveform is one in which all pixels along an electrode in the first set of electrodes are switched to a first display state irrespective of a data waveform applied to the electrodes in the second set of electrodes, each strobe waveform comprising a first pulse in a first time period having a duration of ts and a voltage level, said first pulse immediately followed by a second pulse in a second time period having a duration greater than ts and a voltage level of a greater amplitude than the voltage level during the first time period,
• generating two data waveforms of alternating positive and negative value pulses with one data waveform pulse the inverse of the other data waveform pulse, each data waveform pulse having a duration ts;
• applying one of said two non-blanking strobe waveforms separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes until all electrodes in the first set of electrodes have received said one of said strobe waveforms, t hen applying the other of said two non-blanking strobe waveforms separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes,
• applying one of said two data waveforms for a time period of 2ts to each electrode in the second set of electrodes synchronized with the start of the strobe waveform applied to each electrode in the first set of electrodes, whereby each intersection is addressed with the resultant of said strobe waveform and appropriate data waveform to turn selected intersections to a desired display state once per complete display address period.

A method of multiplex addressing a ferroelectric liquid crystal matrix display comprising a layer of liquid crystal material contained between two cell walls carrying electrodes formed as a first set of electrodes on one cell wall and a second set of electrodes on the other cell wall, the electrodes comprising a matrix of addressable intersections, at least one of the cell walls being surface treated to provide surface alignment to liquid crystal molecules along a single direction, said method comprising the steps of:

• generating two data waveforms of alternating positive and negative value pulses with one data waveform pulse the inverse of the other data waveform pulse, each data waveform pulse having a duration ts,
• generating for each electrode in the first set of electrodes a blanking waveform of duration greater than Its and an amplitude such that all pixels along an electrode in the first set of electrodes are switched to a first display state irrespective of which of said two data waveforms are applied to the electrodes in the second set of electrodes,
• generating for each electrode in the first set of electrodes a non-blanking strobe waveform comprising a first pulse in a first time period having a duration of its and a voltage level, said first pulse immediately followed by a second pulse in a second time period having a duration greater than Its and a voltage level of a greater amplitude than the voltage level during the first time period,
• applying said blanking waveform separately to each electrode in the first set of electrodes with a time delay of 2ts between the start of blanking waveforms being applied to any two electrodes in the first set of electrodes,
• applying said strobe waveform separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes, and
• applying one of said two data waveforms for a time period of 2ts to each electrode in the second set of electrodes synchronized with the start of the strobe waveform applied to each electrode in the first set of electrodes, whereby each intersection is addressed with the resultant of said strobe waveform and appropriate data waveform to turn selected intersections to a desired display state once per complete display address period.

A multiplex addressed ferroelectric liquid crystal matrix display comprising:

• a liquid crystal cell comprising a layer of liquid crystal material contained between two cell walls carrying electrodes formed as a first set of electrodes on one cell wall and a second set of electrodes on the other cell wall, the electrodes comprising a matrix of addressable intersections, at least one of the cell walls being surface treated to provide surface alignment to liquid crystal molecules along a single direction;
• a strobe waveform generator for generating for each electrode in the first set of electrodes two non-blanking strobe waveforms of opposite polarity, wherein a blanking waveform is one in which all pixels along an electrode in the first set of electrodes are switched to a first display state irrespective of a data waveform applied to the electrodes in the second set of electrodes, each strobe waveform comprising a first pulse in a first time period having a duration of ts and a voltage level, said first pulse immediately followed by a second pulse in a second time period having a duration greater than ts and a voltage level of a greater amplitude than the voltage level during the first time period,
• a data waveform generator for generating two data waveforms of alternating positive and negative value pulses with one data waveform pulse the inverse of the other data waveform pulse, each data waveform pulse having a duration ts;
• at least one driver circuit for applying one of said two non-blanking strobe waveforms separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes until all electrodes in the first set of electrodes have received said one of said strobe waveforms, then applying the other of said two non-blanking strobe waveforms separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes,
• at least one driver circuit for applying one of said two data waveforms for a time period of 2ts to each electrode in the second set of electrodes synchronized with the start of the strobe waveform applied to each electrode in the first set of electrodes, whereby each intersection is addressed with the resultant of said strobe waveform and appropriate data waveform to turn selected intersections to a desired display state once per complete display address period.

A multiplex addressed ferroelectric liquid crystal matrix display comprising:

• a liquid crystal cell comprised of a layer of liquid crystal material contained between two cell walls carrying electrodes formed as a first set of electrodes on one cell wall and a second set of electrodes on the other cell wall, the electrodes comprising a matrix of addressable intersections, at least one of the cell walls being surface treated to provide surface alignment to liquid crystal molecules along a single direction;
• a data waveform generator for generating two data waveforms of alternating positive and negative value pulses with one data waveform pulse the inverse of the other data waveform pulse, each data waveform pulse having a duration ts,
• a blanking waveform generator for generating for each electrode in the first set of electrodes a blanking waveform of duration greater than 1ts and an amplitude such that all pixels along an electrode in the first set of electrodes are switched to a first display state irrespective of which of said two data waveforms are applied to the electrodes in the second set of electrodes,
• a strobe waveform generator for generating for each electrode in the first set of electrodes a non-blanking strobe waveform comprising a first pulse in a first time period having a duration of its and a voltage level, said first pulse immediately followed by a second pulse in a second time period having a duration greater than its and a voltage level of a greater amplitude than the voltage level during the first time period,
• at least one driver circuit for applying said blanking waveform separately to each electrode in the first set of electrodes with a time delay of 2ts between the start of blanking waveforms being applied to any two electrodes in the first set of electrodes,
• at least one driver circuit for applying said strobe waveform separately to each electrode in the first set of electrodes in synchronism with said data waveforms with a time delay of 2ts between the start of strobe waveforms being applied to any two electrodes in the first set of electrodes, and
• at least one driver circuit for applying one of said two data waveforms for a time period of 2ts to each electrode in the second set of electrodes synchronized with the start of the strobe waveform applied to each electrode in the first set of electrodes, whereby each intersection is addressed with the resultant of said strobe waveform and appropriate data waveform to turn selected intersections to a desired display state once per complete display address period.