High-speed driving method of a liquid crystal

• US 6,567,063 B1
• Filed: 04/08/1999
• Issued: 05/20/2003
• Est. Priority Date: 04/10/1998
• Status: Expired due to Term

• Current Assignee: HDT, Inc., Masaya Okita
• Original Assignee: Masaya Okita, Rise Incorporated (SoftBank Group Corp.)
• Inventors: Okita, Masaya
• Primary Examiner(s): Mengistu, Amare
• Application Number:
  US09/285,895
• Time in Patent Office: 1,503 Days
• Field of Search: 345/89, 345/95, 345/147, 345/102, 345/150, 345/94, 345/96, 252/299.62
• US Class Current: 345/94
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

In order to drive a liquid crystal at a speed equivalent to or higher than CRT displays, in a liquid crystal display device made of a liquid crystal and two electrodes sandwiching the liquid crystal to display images by applying a voltage based on gradation data between the two electrodes, a predetermined voltage independent from the gradation data is applied across the two electrodes for a predetermined length of time in predetermined intervals.

Claims

1. A high-speed driving method of a liquid crystal for a liquid crystal display device comprising a liquid crystal and two electrodes sandwiching the liquid crystal to display images, the method comprising:

applying a voltage based on gradation data between the two electrodes for a portion of a predetermined interval; and

applying a plurality of predetermined voltages different in absolute value and independent from the gradation data across the two electrodes, a first one of the predetermined voltages being applied for a different predetermined portion of the predetermined interval, the predetermined interval comprising an interval including a single backlight signal.

2. The high-speed driving method of a liquid crystal according to claim 1, including turning ON and OFF illumination once in the predetermined interval to provide the single backlight signal during a part of the portion of the interval that the voltage corresponding to the gradation data is applied.

3. The high-speed driving method of a liquid crystal according to claim 2, wherein the illumination is not applied during the portion of the predetermined interval that the first predetermined voltage independent from the gradation data is applied.

4. The high-speed driving method of a liquid crystal according to claim 1, including emitting red, green and blue color for the liquid crystal sequentially providing the single backlight signal having a single color during each one of the intervals.

5. The high-speed driving method of a liquid crystal according to claim 4, wherein colors are not applied during the portion of the predetermined interval that the first predetermined voltage independent from the gradation data is applied.

6. The high-speed driving method of a liquid crystal according to claim 1, wherein the voltage across the two electrodes is inverted in polarity within each said predetermined interval so that the average value of the voltage across the two electrodes is approximately 0 volts for each of the intervals.

7. The high-speed driving method of a liquid crystal according to claim 1, wherein an absolute value of the first predetermined voltage is larger than a maximum value among absolute values of the voltage based on the gradation data.

8. The high-speed driving method of a liquid crystal according to claim 1, including the step of heating the liquid crystal to a predetermined temperature value.

9. A high-speed driving method of a TN liquid crystal for a liquid crystal display device comprising a TN liquid crystal and two electrodes sandwiching the liquid crystal to display images comprising:

applying a voltage based on gradation data between the two electrodes during a first predetermined length of time of a predetermined interval; and

applying at least first and second predetermined voltages different in absolute value and independent from the gradation data across the two electrodes for second and third predetermined lengths of time, the at least second and third predetermined lengths of time being separate from the first length of time such that the first predetermined length of time and the at least second and third separate lengths of time equal the predetermined interval.

10. The high-speed driving method of a TN liquid crystal according to claim 9, including the step of illuminating the liquid crystal ON and OFF during each of the predetermined intervals.

11. The high-speed driving method of a TN liquid crystal according to claim 10, wherein illuminating of the liquid crystal is turned OFF when the at least first and second predetermined voltages independent from the gradation data are applied.

12. The high-speed driving method of a TN liquid crystal according to claim 9, including the step of emitting red, green and blue colors for the liquid crystal sequentially by providing a single color during each of the predetermined time intervals.

13. The high-speed driving method of a TN liquid crystal according to claim 12, wherein the colors are not applied when the at least second and third predetermined voltages independent from the gradation data are applied.

14. The high-speed driving method of a TN liquid crystal according to claim 9, wherein the voltage across the two electrodes is inverted in polarity within each said predetermined interval so that the average value of the voltage across the two electrodes is approximately 0 volts for each of the predetermined intervals.

15. The high-speed driving method of a TN liquid crystal according to claim 9, wherein an absolute value of at least one of the predetermined voltages is larger than a maximum value among absolute values of the voltage based on the gradation data.

16. The high-speed driving method of a TN liquid crystal according to claim 9, including the step of heating the liquid crystal to a predetermined temperature value.

17. The high-speed driving method of a TN liquid crystal according to claim 9, wherein each predetermined interval is defined as a time period including a single backlight signal.

18. A high-speed driving method of a liquid crystal for an active matrix liquid crystal display device having a plurality of elements in the form of a matrix, each said element including a liquid crystal, two electrodes sandwiching the liquid crystal and an active device connected to one of the electrodes, the method including the steps of displaying images by applying a voltage based on gradation data between the two electrodes for a first predetermined length of time of a predetermined interval, and

applying at least a second predetermined voltage different in absolute value and independent from the gradation data across the two electrodes for a second predetermined length of time in the predetermined interval, the second predetermined length of time being separate from the first predetermined length of time.

19. The highspeed driving method of a liquid crystal according to claim 18, including the step of illuminating the liquid crystal during a portion of the first predetermined length of time.

20. The high-speed driving method of a liquid crystal according to claim 19, including not illuminating the liquid crystal during the second predetermined length of time for applying the second predetermined voltage independent from the gradation data.

21. The high-speed driving method of a liquid crystal according to claim 18, including the step of emitting red, green and blue colors to the liquid crystal separately and sequentially by providing one of the colors during each of the predetermined intervals.

22. The high-speed driving method of a liquid crystal according to claim 21, wherein the colors are not applied during the second predetermined length of time the second predetermined voltage independent from the gradation data is applied.

23. The high-speed driving method of a liquid crystal according to claim 18, wherein the voltage across the two electrodes is inverted in polarity within each said predetermined interval to provide an average value of the voltage across the two electrodes of approximately 0 volts for each of the intervals.

24. The high-speed driving method of a liquid crystal according to claim 18, wherein an absolute value of the second predetermined voltage is larger than the maximum value among absolute values of the voltage based on the gradation data.

25. The high-speed driving method of a liquid crystal according to claim 18, including the step of heating the liquid crystal to a predetermined temperature value.

26. The high-speed driving method of a liquid crystal according to claim 18, wherein each predetermined interval is defined as a time period including a single backlight signal.

27. A high-speed method of driving a liquid crystal display panel having liquid crystals sandwiched by pairs of electrodes to display images, comprising the steps of:

applying in sequence differently colored backlight signals to the electrodes during predetermined time intervals, the colored backlight signals corresponding to the predetermined time intervals such that a single one of the colored backlight signals is applied during each of the time intervals, the colored backlight signals each being provided for a first predetermined length of time which is less than the corresponding time interval;

applying a display voltage across the pairs of electrodes based on gradation data for a second predetermined length of time during each of the time intervals, the display voltage varying for each of the time intervals based on the gradation data; and

applying an independent voltage across the pairs of electrodes independent from the display voltage for a third predetermined length of time during each of the time intervals, the independent voltage applied having the same voltage value for each of the predetermined intervals.

28. The high-speed driving method of claim 27, wherein the step of providing in sequence the differently colored backlight signals to the liquid crystals comprises providing the colors red, green and blue in sequence and then repeating the sequence of colors.

29. The high-speed driving method of claim 27, wherein the step of applying the independent voltage across the electrodes for the third predetermined length of time results in the optical transmittance of the liquid crystal returning to or remaining black during a portion of each of the predetermined intervals.

30. The high-speed driving method of claim 27, wherein the step of applying the independent voltage across the electrodes for the third predetermined length of time results in the optical transmittance of the liquid crystal returning to or remaining white during a portion of each of the predetermined intervals.

31. The high-speed driving method of claim 27, wherein the step of applying the independent voltage independent from the display voltage across the electrodes for the third predetermined length of time includes beginning application of the independent voltage when the first predetermined length of time that the backlight signals are applied ends.

32. The high-speed driving method of claim 27, wherein the independent voltage applied to the electrodes comprises a first independent voltage, the method including the step of applying a second independent voltage independent from the display voltage and having an absolute value of zero volts across the electrodes for a fourth predetermined length of time, the fourth predetermined length of time being a first portion of the predetermined interval separate from a second portion of the predetermined interval when the first independent voltage is applied for the third predetermined length of time.

33. An active matrix liquid crystal display device having a plurality of elements in the form of a matrix, each said element comprising:

a liquid crystal;

two electrodes sandwiching the liquid crystal; and

an active device connected to said electrodes to display images by applying a display voltage between the electrodes based on gradation data for a first time period within a predetermined interval and applying an independent voltage independent from the display voltage between the electrodes for a second time period separate from the first time period within the predetermined time interval;

wherein an illuminator sequentially emits red, green and blue colors to the liquid crystal, a single one of the three colors being emitted during the predetermined time interval.

34. The active matrix liquid crystal display device of claim 33, wherein the independent voltage comprises a first, independent voltage and the active device applies a second independent voltage independent from the gradation data for a third time period within the predetermined time interval, the third time period being separate from the first and second time periods.

35. The active matrix liquid crystal display device of claim 33, wherein the single one of the three colors is emitted to the liquid crystal during part of the predetermined time interval when the display voltage is applied to the electrodes and the single one of the three colors is not emitted when the first independent voltage is applied to the electrodes.