Method of driving bi-stable liquid crystal panel and driving device
In method of driving a bistable nematic dot-matrix liquid crystal display panel, a first pulse voltage is applied to nematic liquid crystal molecules to raise the nematic liquid crystal molecules in the longitudinal direction. After application of the first pulse voltage, a second pulse voltage is applied to the nematic liquid crystal molecules for selecting one of two stable orientation states of the nematic liquid crystal molecules. Immediately after the application of the second pulse voltage, an AC pulse waveform of a voltage lower than a last pulse of the second pulse voltage is applied to thereby remove residual electric charges remaining in the bistable nematic dot-matrix liquid crystal display panel.
1. A method of driving a bistable nematic dot-matrix liquid crystal display panel capable of selecting black/white only by positive polarity driving or negative polarity driving, the method comprising:
applying a first pulse voltage to nematic liquid crystal molecules of the bistable nematic dot-matrix liquid crystal display panel to raise the nematic liquid crystal molecules in the longitudinal direction;
after application of the first pulse voltage, applying a second pulse voltage to the nematic liquid crystal molecules for selecting one of two stable orientation states of the nematic liquid crystal molecules; and
immediately after application of the second pulse voltage, applying an AC pulse waveform of a voltage lower than a last pulse of the second pulse voltage to thereby remove residual electric charges remaining in the bistable nematic dot-matrix liquid crystal display panel.
2. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 1 , wherein the AC pulse waveform is a rectangular AC pulse waveform.
3. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 1 , wherein the applying of the AC pulse waveform comprises changing a voltage, a pulse width, or a number of pulses of the AC pulse waveform depending on temperature.
4. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 1 , wherein the applying of the AC pulse waveform comprises gradually changing a voltage of the AC pulse waveform to be 0 V.
5. A device for driving a bistable nematic dot-matrix liquid crystal display panel capable of selecting black/white only by positive polarity driving or negative polarity driving, the device comprising:
a common driving section for driving common lines in the horizontal direction;
a segment driving section for driving segment lines in the vertical direction;
a power supply circuit for generating drive potentials; and
a control section for controlling the common driving section, the segment driving section, and the power supply circuit to apply a first pulse voltage to nematic liquid crystal molecules of the bistable nematic dot-matrix liquid crystal display panel to raise the nematic liquid crystal molecules in the longitudinal direction, apply a second pulse voltage to the nematic liquid crystal molecules for selecting one of two stable orientation states of the nematic liquid crystal molecules, and immediately thereafter apply an AC pulse waveform of a voltage lower than a last pulse of the second pulse voltage to thereby remove charges remaining in the bistable nematic dot-matrix liquid crystal display panel.
6. A device for driving a bistable nematic dot-matrix liquid crystal display panel according to claim 5 , wherein the AC pulse waveform is a rectangular AC pulse waveform.
7. A device for driving a bistable nematic dot-matrix liquid crystal display panel according to claim 5 , wherein the control section further controls the common driving section, the segment driving section, and the power supply circuit to change a voltage, a pulse width, or a number of pulses of the AC pulse waveform depending on temperature.
8. A device for driving a bistable nematic dot-matrix liquid crystal display panel according to claim 5 , wherein the control section controls the common driving section, the segment driving section, and the power supply circuit so that a voltage of the AC pulse waveform is gradually changed to be 0 V.
9. A method of driving a bistable nematic dot-matrix liquid crystal display panel capable of selecting black/white only by positive polarity driving or negative polarity driving, the method comprising:
applying a first pulse voltage to nematic liquid crystal molecules of the bistable nematic dot-matrix liquid crystal display panel to raise the nematic liquid crystal molecules in the longitudinal direction;
after application of the first pulse voltage, applying a second pulse voltage to the nematic liquid crystal molecules for selecting one of two stable orientation states of the nematic liquid crystal molecules; and
immediately after application of the second pulse voltage, applying a cancel AC pulse waveform with a gradual decrease in voltage to remove a parasite signal.
10. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 9 , wherein the cancel AC pulse waveform is a rectangular cancel AC pulse waveform.
11. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 9 , wherein the applying of the cancel AC pulse waveform comprises changing a voltage, a pulse width, or a number of pulses of the cancel AC pulse waveform depending on temperature.
12. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 9 , wherein the voltage of the cancel AC pulse waveform is gradually decreased to 0 V.
13. A method of driving a bistable nematic dot-matrix liquid crystal display panel according to claim 9 , wherein the cancel AC pulse waveform is a low voltage cancel AC pulse waveform.