Liquid crystal apparatus and driving method

A liquid crystal apparatus, comprising:

• a liquid crystal device comprising scanning electrodes, data electrodes intersecting with the scanning electrodes, and a chiral smectic liquid crystal having a threshold voltage disposed between the scanning electrodes and the data electrodes so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, and
• voltage application means for:
• applying a scanning selection signal to the scanning electrodes,
• applying data signals to the data electrodes in synchronism with the scanning selection signal so that pixels at the intersection of a non-selected scanning electrode not receiving the scanning selection signal and the data electrodes receive an AC voltage superposed with a DC voltage not exceeding the threshold voltage of the chiral smectic liquid crystal, and
• inverting a polarity of the DC voltage.

A liquid crystal apparatus, comprising:

• (a) A liquid crystal device comprising scanning electrodes and data electrodes intersecting the scanning electrodes so as to form an electrode matrix, and a chiral smectic liquid crystal disposed between the scanning electrodes and the data electrodes so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, said chiral smectic liquid crystal switching from a first orientation state to a second orientation state by application of a voltage exceeding a first threshold and switching from the second orientation state to the first orientation state by application of a voltage exceeding a second threshold;
• (b) voltage application means for:
• sequentially applying a scanning selection signal to the scanning electrodes to effect one vertical scanning, the scanning selection signal having a voltage of a first polarity or a voltage of a second polarity with reference to a voltage level of a scanning electrode not receiving the scanning selection signal,
• applying data signals to the data electrodes in synchronism with the scanning selection signal, thereby to apply a voltage signal causing a switching from the first orientation state to the second orientation state or a switching from the second orientation state to the first orientation state to pixels at intersections of a scanning electrode receiving the scanning selection signal and the data electrodes, and to apply to intersections of scanning electrodes not receiving the scanning selection signal and the data electrodes a voltage signal which does not exceed either the first or second threshold and comprises an AC waveform superposed with a constant DC voltage in one vertical scanning period, and
• (c) means for periodically changing a polarity of the constant DC voltage.

A liquid crystal apparatus, comprising:

• (a) a liquid crystal panel comprising scanning electrodes and data electrodes intersecting the scanning electrodes so as to form an electrode matrix, and a chiral smectic liquid crystal disposed so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, and
• (b) drive means for:
• sequentially applying a first scanning selection signal to the scanning electrodes to effect a first vertical scanning, said first scanning selection signal comprising a voltage signal of a first polarity and a voltage signal of a second polarity in a first phase and a second phase, respectively;
• and sequentially applying a second scanning selection signal to the scanning electrodes to effect a second vertical scanning, the second scanning selection signal comprising a voltage of the second polarity and a voltage of the first polarity in the first phase and the second phase, respectively;
• the first polarity and the second polarity being determined with reference to a voltage level of a scanning electrode not receiving any of the first and second scanning selection signals, the first phase being longer than the second phase;
• applying to pixels at intersection of scanning electrodes not receiving any of the first and second scanning selection signals and the data electrodes a voltage signal of an AC waveform superposed with a DC component which is constant in one vertical scanning period;
• and
• inverting a polarity of the DC component for each one vertical scanning.

A liquid crystal apparatus, comprising:

• (a) a liquid crystal device comprising scanning electrodes and data electrodes intersecting the scanning electrodes so as to form an electrode matrix, and a liquid crystal disposed between the scanning electrodes and the data electrodes so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, said liquid crystal having a memory characteristic of switching from a first memory state to a second memory state by application of a voltage exceeding one threshold and switching from the second memory state to the first memory state by application of a voltage exceeding another threshold, and
• (b) voltage application means for
• sequentially applying a scanning selection signal to the scanning electrodes to effect one vertical scanning, said scanning selection signal having a voltage of one polarity or a voltage of the other polarity with reference to a voltage level of a scanning electrode not receiving the scanning selection signal;
• and
• applying to the data electrodes data signals in synchronism with the scanning selection signal and a DC voltage which has a polarity alternating in a period synchronized with said one vertical scanning period,
• thereby to apply a voltage signal causing a switching from the first memory state to the second memory state or a switching from the second memory state to the first memory state to pixels at intersections of a scanning electrode receiving the scanning selection signal and the data electrodes, and to apply to intersections of scanning electrodes not receiving the scanning selection signal and the data electrodes a voltage signal which does not exceed either said one or another threshold.

A liquid crystal apparatus, comprising:

• (a) a liquid crystal device comprising scanning electrodes and data electrodes intersecting the scanning electrodes so as to form an electrode matrix, and a chiral smectic liquid crystal disposed between the scanning electrodes and the data electrodes so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, said chiral smectic liquid crystal switching from a first orientation state to a second orientation state by application of a voltage exceeding one threshold and switching from the second orientation state to the first orientation state by application of a voltage exceeding another threshold, and
• (b) voltage application means for
• sequentially applying a scanning selection signal to the scanning electrodes to effect one vertical scanning, said scanning selection signal having a voltage of one polarity of a voltage of the other polarity with reference to a voltage level of a scanning electrode not receiving the scanning selection signal, and
• applying to the data electrodes data signals in synchronism with the scanning selection signal and a DC voltage which has a polarity alternating in a period synchronized with said one vertical scanning period,
• thereby to apply a voltage signal causing a switching from the first orientation state to the second orientation state or a switching from the second orientation state to the first orientation state to pixels at intersections of a scanning electrode receiving the scanning selection signal and the data electrodes, and to apply to intersections of scanning electrodes not receiving the scanning selection signal and the data electrodes a voltage signal which does not exceed either said one or another threshold.

A liquid crystal apparatus, comprising:

• (a) a liquid crystal device comprising scanning electrodes and data electrodes intersecting the scanning electrodes so as to form an electrode matrix, and a liquid crystal disposed between the scanning electrodes and the data electrodes so as to form a pixel at each intersection of the scanning electrodes and the data electrodes, said liquid crystal having a memory characteristic of switching from a first optical state to a second optical state by application of a voltage exceeding one threshold and switching from the second optical state to the first optical state by application of a voltage exceeding another threshold, and
• (b) voltage application means for
• sequentially applying a scanning selection signal to the scanning electrodes to effect one vertical scanning, said scanning selection signal having a voltage of one polarity or a voltage of the other polarity with reference to a voltage level of a scanning electrode not receiving the scanning selection signal, and
• applying to the data electrodes data signals in synchronism with the scanning selection signal and a DC voltage which has a polarity alternating in a period synchronized with said one vertical scanning period,
• thereby to apply a voltage signal causing a switching from the first optical state to the second optical state or a switching from the second optical state to the first optical state to pixels at intersections of a scanning electrode receiving the scanning selection signal and the data electrodes, and to apply to intersections of scanning electrodes not receiving the scanning selection signal and the data electrodes a voltage signal which does not exceed either said one or another threshold.