Liquid crystal display element, method of driving the same, and electronic paper using the same

1. A method of driving a liquid crystal display element that applies an AC pulse voltage to drive liquid crystal, the method comprising:

comparing the temperature of the liquid crystal with a reference temperature;

when the temperature of the liquid crystal is higher than the reference temperature, generating the AC pulse voltage for a high temperature having a pulse width that is shorter than a reference pulse width of a reference AC pulse voltage used at the reference temperature; and

applying the AC pulse voltage for the high temperature to the liquid crystal in a period that is equal to the reference pulse width,

wherein the AC pulse voltage for the high temperature is generated by a voltage cut off signal that forcibly turns off the voltage level of the reference AC pulse voltage during an arbitrary period.

2. The method of driving the liquid crystal display element according to claim 1 ,

wherein the voltage cut off signal is asserted during the time which includes a time point of the polarity reversal of the reference AC pulse voltage.

3. The method of driving the liquid crystal display element according to claim 2 ,

wherein the period from the start of the assertion of the voltage cut off signal to the time point of the polarity reversal is equal to the period from the time point of the polarity reversal to the end of the assertion of the voltage cut off signal.

4. The method of driving the liquid crystal display element according to claim 1 ,

wherein the voltage cut off signal is asserted at both sides of the time which includes a time point of the polarity reversal of the reference AC pulse voltage.

5. The method of driving the liquid crystal display element according to claim 4 ,

wherein the voltage cut off signal is asserted during a first period from a start of the reference AC pulse voltage to a first time before the polarity reversal and during a second period from a second time after the polarity reversal to an end of the reference AC pulse voltage.

6. The method of driving the liquid crystal display element according to claim 5 ,

wherein the first period and the second period have the same length.

7. The method of driving the liquid crystal display element according to claim 1 ,

wherein the reference temperature is a room temperature.

8. The method of driving the liquid crystal display element according to claim 2 ,

wherein the polarity reversal occurs in the middle of the reference pulse width.

9. The method of driving the liquid crystal display element according to claim 1 ,

wherein the liquid crystal is cholesteric liquid crystal.

10. The method of driving the liquid crystal display element according to claim 9 ,

wherein the liquid crystal changes to a planar state that selectively reflects a specific light wavelength in a reset process.

11. The method of driving the liquid crystal display element according to claim 1 ,

wherein the transmission rate of image data to a control unit that generates the AC pulse voltage for a high temperature at a temperature that is higher than the reference temperature is equal to that at the reference temperature.

12. A liquid crystal display element for applying an AC pulse voltage to liquid crystal to display an image, comprising:

a control unit that, when the temperature of the liquid crystal is higher than a reference temperature, generates an AC pulse voltage for a high temperature having a pulse width that is shorter than a reference pulse width of a reference AC pulse voltage used at the reference temperature; and

a driver that applies the AC pulse voltage for the high temperature to the liquid crystal in a period that is equal to the reference pulse width,

wherein the control unit generates the AC pulse voltage for the high temperature using a voltage cut off signal that forcibly turns off the voltage level of the reference AC pulse voltage during an arbitrary period.

13. The liquid crystal display element according to claim 12 ,

wherein the voltage cut off signal is asserted during the time which includes a time point of the polarity reversal of the reference AC pulse voltage.

14. The liquid crystal display element according to claim 13 ,

wherein the period from the start of the assertion of the voltage cut off signal to the time point of the polarity reversal is equal to the period from the time point of the polarity reversal to the end of the assertion of the voltage cut off signal.

15. The liquid crystal display element according to claim 12 ,

wherein the voltage cut off signal is asserted at both sides of the time which includes a time point of the polarity reversal of the reference AC pulse voltage.

16. The liquid crystal display element according to claim 15 ,

wherein the voltage cut off signal is asserted during a first period from a start of the reference AC pulse voltage to a first time before the polarity reversal and during a second period from a second time after the polarity reversal to an end of the reference AC pulse voltage.

17. The liquid crystal display element according to claim 16 ,

wherein the first period and the second period have the same length.

18. An electronic paper for displaying an image comprising:

the liquid crystal display element according to claim 12 .