Liquid Crystal Display Device and Driving Method Thereof, Television Receiver, Liquid Crystal Display Program, Computer-Readable Storage Medium Storing the Liquid Crystal Display Program, and Drive Circuit

• US 20090115772A1
• Filed: 12/19/2006
• Published: 05/07/2009
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yamada, Naoshi, Sawahata, Junichi, Shiomi, Makoto, Tsubata, Toshihide, Uchida, Toshihisa
• Granted Patent: US 8,786,535 B2
• Time in Patent Office: Days
• US Class Current: 345/214
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

In one embodiment of the present invention, a driving method of a liquid crystal display device is disclosed. According to one embodiment of the present invention a driving method of an active matrix display device is disclosed including: a plurality of source lines; a plurality of gate lines that intersect the source lines; and a plurality of pixel formation sections being disposed in a matrix manner at the respective intersections of the source lines and the gate lines, each of the pixel formation sections receiving as a pixel value a voltage applied to the source line that passes through the corresponding intersection when the gate line that passes through the corresponding intersection is selected, wherein non-image signals are applied to the source lines in each horizontal scanning period, and the gate lines are selected in an effective scanning period, and thereafter the gate lines are selected, in sync with a timing of application of the non-image signals to the source lines, before the subsequent effective scanning period comes after a point in time when the gate lines have been brought into non-selected state.

Claims

1. A driving method of an active matrix type liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected, wherein

non-image signals are applied to the data signal lines at a boundary point between the adjacent horizontal scanning periods, and

the scanning signal lines are selected in an effective scanning period, and thereafter the scanning signal lines are selected, in sync with a timing of application of the non-image signals to the data signal lines, before the subsequent effective scanning period comes after a point in time when the scanning signal lines have been brought into non-selected state.

2. The driving method according to claim 1, wherein

the liquid crystal display device is a liquid crystal display device of vertical alignment mode in which a direction where liquid crystal molecules are aligned is controlled by an electric field, and

the non-image signal is a pre-tilt signal by which the liquid crystal molecules are pre-tilted.

3. The driving method according to claim 1, wherein

a polarity of a voltage corresponding to the non-image signal is identical with a polarity of a voltage corresponding to an image signal in a horizontal scanning period immediately after application of the non-image signal.

4. The driving method according to claim 1, wherein

a polarity of a non-image signal selected at the end of one vertical scanning period and applied to the pixel section is identical with a polarity of an image signal selected in a subsequent vertical scanning period.

5. The driving method according to claim 2, wherein

in a case where display luminance T when white luminance level is 1 and black luminance level is 0 is nearly close to T=(L/Lw)^γ

where L is display grayscale level, Lw is white display grayscale, and γ

is γ

characteristics, the pre-tilt signal is a signal indicating Lw×

10<sup>(−

3/γ

)</sup> or greater.

6. The driving method according to claim 2, wherein

regarding γ

indicating γ

characteristics, display grayscale L is defined as;

L=255×

T^(1/2.2) where T is display luminance when white luminance level is 1 and black luminance level is 0, and

the pre-tilt signal is a signal that generates a grayscale voltage higher than a grayscale voltage obtained when L=12.

7. The driving method according to claim 5, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 12th grayscale level or higher level out of 256 display grayscale levels.

8. The driving method according to claim 5, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 45th grayscale level or higher level out of 1024 grayscale levels for display.

9. The driving method according to claim 2, wherein

when luminance level of white display is 100% and luminance level of black display is 0%, luminance level of the pre-tilt signal is not less than 0.1%.

10. The driving method according to claim 1, wherein

application of the non-image signals to the data signal lines is performed with adjacent data signal lines short-circuited to each other.

11. The driving method according to claim 10, wherein

application of the non-image signals to the data signal lines is performed by application of a fixed voltage to each of the data signal lines.

12. The driving method according to claim 1, wherein

each of the non-image signals is a voltage that exists between voltages whose polarities are opposite to each other, and

application of the non-image signal to the data signal lines is performed at polarity reversal of a data signal.

13. The driving method according to claim 12, wherein

at a time when a polarity of a signal on the data signal line is reversed in each horizontal scanning period, the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is an even-number.

14. The driving method according to claim 1, wherein

application of the non-image signals to the data signal lines is performed by application of a voltage whose polarity is reversed in each vertical scanning period commonly to the data signal lines.

15. The driving method according to claim 1, wherein

application of the non-image signals to the data signal lines is performed by application of a voltage whose polarity is reversed in each horizontal scanning period.

16. The driving method according to claim 1, wherein

application of the non-image signals to the data signal lines is performed by application of voltages whose polarities are reversed in each horizontal scanning period, the voltages on the adjacent data signal lines being opposite in polarity to each other.

17. The driving method according to claim 1, wherein

a polarity of a signal on the data signal line is reversed every plural horizontal scanning periods.

18. The driving method according to claim 17, wherein

the non-image signal is applied to the data signal line when a polarity of a data signal is not reversed in between adjacent horizontal periods.

19. The driving method according to claim 17, wherein

at a time when the polarity of the signal on the data signal line is reversed every n-number (n is an integer not less than 2) of horizontal scanning periods, the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is a multiple number of n.

20. The driving method according to claim 19, wherein

the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is a multiple number of 2n.

21. The driving method according to claim 17, wherein

application of the non-image signals to the data signal lines is performed by application of fixed voltages to each of the data signal lines, and

polarities of the fixed voltages are reversed every plural horizontal scanning periods.

22. The driving method according to claim 21, wherein

the fixed voltages are voltages whose polarities are reversed every plural horizontal scanning periods, and the fixed voltages applied on the adjacent data signal lines are opposite in polarity to each other.

23. The driving method according to claim 1, wherein

the liquid crystal display device performs overshoot driving, and

amounts of grayscale correction in the overshoot driving are found in accordance with polarities of pixels and video signals obtained from an external entity.

24. The driving method according to claim 23, wherein

the amounts of grayscale correction for use in the overshoot driving are found by using a lookup table in which the polarities of the pixels and the video signals obtained from the external entity are associated with each other.

25. The driving method according to claim 1, wherein

the liquid crystal display device performs overshoot driving, and

after amounts of overshoot correction in the overshoot driving are found in relation to video signals obtained from an external entity, amounts of grayscale correction are found by using a lookup table in which polarities of pixels and the amounts of overshoot correction are associated with each other.

26. The driving method according to claim 1 wherein

the liquid crystal display device has a backlight, and

the backlight is turned off in sync with the timing of application of the non-image signal to the data signal line.

27. The driving method according to claim 1 wherein

a duration of application of the non-image signal to the data signal line is shorter than a duration of application of an image signal for image display which signal is applied to the data signal lines.

28. The driving method according to claim 1 wherein

the liquid crystal display device is a liquid crystal display device of normally black mode in which black display is performed in a state where no voltage is applied.

67. The driving method according to claim 6, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 12th grayscale level or higher level out of 256 display grayscale levels.

68. The driving method according to claim 6, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 45th grayscale level or higher level out of 1024 grayscale levels for display.

29. An active matrix type liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected, wherein

non-image signals are applied to the data signal lines at a boundary point between the adjacent horizontal scanning periods, and

the scanning signal lines are selected in an effective scanning period, and thereafter the scanning signal lines are selected, in sync with a timing of application of the non-image signals to the data signal lines, before the subsequent effective scanning period comes after a point in time when the scanning signal lines have been brought into non-selected state.

30. The liquid crystal display device according to claim 29, wherein

the liquid crystal display device is a liquid crystal display device of vertical alignment mode in which a direction where liquid crystal molecules are aligned is controlled by an electric field, and

the non-image signal is a pre-tilt signal by which the liquid crystal molecules are pre-tilted.

31. The liquid crystal display device according to claim 29, wherein

a polarity of a voltage corresponding to the non-image signal is identical with a polarity of a voltage corresponding to an image signal in a horizontal scanning period immediately after application of the non-image signal.

32. The liquid crystal display device according to claim 29, wherein

a polarity of a non-image signal selected at the end of one vertical scanning period and applied to the pixel section is identical with a polarity of an image signal selected in a subsequent vertical scanning period.

33. The liquid crystal display device according to claim 30, wherein

in a case where display luminance T when white luminance level is 1 and black luminance level is 0 is nearly close to T=(L/Lw)^γ

where L is display grayscale level, Lw is white display grayscale, and γ

is γ

characteristics, the pre-tilt signal is a signal indicating Lw×

10<sup>(−

3/γ

)</sup> or greater.

34. The liquid crystal display device according to claim 30, wherein

regarding γ

indicating γ

characteristics, display grayscale L is defined as;

L=255×

T^(1/2.2) where T is display luminance when white luminance level is 1 and black luminance level is 0, and

the pre-tilt signal is a signal that generates a grayscale voltage higher than a grayscale voltage obtained when L=12.

35. The liquid crystal display device according to claim 33, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 12th grayscale level or higher level out of 256 display grayscale levels.

36. The liquid crystal display device according to claim 33, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 45th grayscale level or higher level out of 1024 grayscale levels for display.

37. The liquid crystal display device according to claim 30, wherein

when luminance level of white display is 100% and luminance level of black display is 0%, luminance level of the pre-tilt signal is not less than 0.1%.

38. The liquid crystal display device according to claim 29, wherein

the adjacent data signal lines are connected capable of being short-circuited to each other, and application of the non-image signals to the data signal lines is performed with the data signal lines short-circuited.

39. The liquid crystal display device according to claim 38, further comprising:

a fixed voltage power source that applies the non-image signals to the data signal lines by applying a common fixed voltage to the data signal lines.

40. The liquid crystal display device according to claim 29, wherein

each of the non-image signals is a voltage that exists between voltages whose polarities are opposite to each other, and

application of the non-image signal to the data signal lines is performed at polarity reversal of a data signal.

41. The liquid crystal display device according to claim 40, wherein

at a time when a polarity of a signal on the data signal line is reversed in each horizontal scanning period, the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is an even-number.

42. The liquid crystal display device according to claim 29, further comprising:

a first polarity reversal power source that applies the non-image signals to the data signal lines by applying a voltage whose polarity is reversed in each vertical scanning period commonly to the data signal lines.

43. The liquid crystal display device according to claim 29, further comprising:

a second polarity reversal power source that applies the non-image signals to the data signal lines by applying a voltage whose polarity is reversed in each horizontal scanning period commonly to the data signal lines.

44. The liquid crystal display device according to claim 43, wherein

the second polarity reversal power source applies the non-image signals commonly to the data signal lines by applying voltages whose polarities are reversed in each horizontal scanning period, the voltages on the adjacent data signal lines being opposite in polarity to each other.

45. The liquid crystal display device according to claim 29, wherein

a polarity of a signal on the data signal line is reversed every plural horizontal scanning periods.

46. The liquid crystal display device according to claim 45, wherein

the non-image signal is applied to the data signal line when a polarity of a data signal is not reversed in between adjacent horizontal periods.

47. The liquid crystal display device according to claim 45, wherein

at a time when the polarity of the signal on the data signal line is reversed every n-number (n is an integer not less than 2) of horizontal scanning periods, the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is a multiple number of n.

48. The liquid crystal display device according to claim 47, wherein

the number of times the scanning signal line is selected in sync with the timing of application of the non-image signal to the data signal line is a multiple number of 2n.

49. The liquid crystal display device according to claim 45, further comprising:

a third polarity reversal power source that applies the non-image signals to the data signal lines by applying a voltage whose polarity is reversed every plural horizontal scanning periods to the data signal lines.

50. The liquid crystal display device according to claim 49, wherein

the third polarity reversal power source applies the non-image signals to the data signal lines by applying to the data signal lines voltages whose polarities are reversed every plural horizontal scanning periods, the voltages on the adjacent data signal lines being opposite in polarity to each other.

51. The liquid crystal display device according to claim 29, wherein

a duration of application of the non-image signal to the data signal line is shorter than a duration of application of an image signal for image display which signal is applied to the data signal lines.

52. The liquid crystal display device according to claim 29, wherein

the liquid crystal display device is a liquid crystal display device of normally black mode in which black display is performed in a state where no voltage is applied.

53. The liquid crystal display device according to of claim 29, further comprising:

polarity information detecting means that detects pieces of polarity information of the pixels; and

correction amount calculating means that finds the amounts of grayscale correction in overshoot driving in accordance with the polarity information and video signals obtained from an external entity.

54. The liquid crystal display device according to claim 53, further comprising:

a lookup table in which the polarities of the pixels and the video signals obtained from the external entity are associated with each other.

55. A liquid crystal display program for operating a liquid crystal display device according to claim 53, the program causing a computer to function as the polarity information detecting means and the correction amount calculating means.

56. A computer-readable storage medium storing a liquid crystal display program according to claim 55.

57. A television receiver comprising:

a liquid crystal display device according to claim 29; and

a tuner section that receives a television broadcast.

69. The liquid crystal display device according to claim 34, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 12th grayscale level or higher level out of 256 display grayscale levels.

70. The liquid crystal display device according to claim 34, wherein

the pre-tilt signal is a signal indicating γ

characteristics of 2.2 and 45th grayscale level or higher level out of 1024 grayscale levels for display.

58. A drive circuit for use in an active matrix type liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected, wherein

non-image signals are applied to the data signal lines at a boundary point between the adjacent horizontal scanning periods, and

the scanning signal lines are selected in an effective scanning period, and thereafter the scanning signal lines are selected, in sync with a timing of application of the non-image signals to the data signal lines, before the subsequent effective scanning period comes after a point in time when the scanning signal lines have been brought into non-selected state.

59. A drive circuit for use in an active matrix type liquid crystal display device, the drive circuit supplying data signals to data signal lines, the liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected,

the drive circuit comprising;

a first polarity reversal power source being connected to the data signal lines and capable of generating voltages whose polarities are reversed,

the first polarity reversal power source generating voltages whose polarities are reversed in each vertical scanning period in sync with a timing of supply of a gate start pulse signal to the first polarity reversal power source, and applying the thus generated voltages as non-image signals respectively to the data signal lines at polarity reversal of the data signals.

60. A drive circuit for use in an active matrix type liquid crystal display device, the drive circuit supplying video signals to data signal lines, the liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected,

the drive circuit comprising;

a second polarity reversal power source being connected to the data signal lines and capable of generating voltages whose polarities are reversed,

the second polarity reversal power source generating voltages whose polarities are reversed in each horizontal scanning period in sync with a timing of supply of a gate clock signal to the second polarity reversal power source, and applying the thus generated voltages as non-image signals respectively to the data signal lines at polarity reversal of data signals.

61. A drive circuit for use in an active matrix type liquid crystal display device, the drive circuit supplying video signals to data signal lines, the liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected,

the drive circuit comprising;

a second polarity reversal power source being connected to the data signal lines and capable of generating voltages whose polarities are reversed,

the second polarity reversal power source generating voltages whose polarities are reversed in each horizontal scanning period in sync with a timing of supply of a gate clock signal to the second polarity reversal power source, and applying the thus generated voltages as non-image signals respectively to odd-numbered lines of the data signal lines at polarity reversal of data signals while applying voltages which are opposite in polarity to the thus generated voltages as the non-image signals respectively to even-numbered lines of the data signal lines at polarity reversal of data signals.

62. A drive circuit supplying video signals to a plurality of data signal lines, comprising:

a constant-voltage diodes being connected respectively to the data signal lines; and

a fixed voltage power source, connected to the data signal lines via the respective constant-voltage diodes, applying a common fixed voltage as an non-image signal to the data signal lines at polarity reversal of data signals.

63. A drive circuit supplying video signals to a plurality of data signal lines, comprising:

a third polarity reversal power source being connected to the data signal lines and capable of generating voltages whose polarities are reversed,

the third polarity reversal power source generating voltages whose polarities are reversed every plural horizontal scanning periods, and applying the thus generated voltages as non-image signals respectively to the data signal lines.

64. The drive circuit according to claim 63, wherein

the third polarity reversal power source generates voltages whose polarities are reversed every plural horizontal scanning periods, and applies the thus generated voltages as non-image signals respectively to odd-numbered data signal lines of the data signal lines while applying voltages which are opposite in polarity to the thus generated voltages as the non-image signals respectively to even-numbered data signal lines of the data signal lines.

65. A driving method of an active matrix type liquid crystal display device comprising:

a plurality of data signal lines;

a plurality of scanning signal lines that intersect the data signal lines; and

a plurality of pixel sections being disposed in a matrix manner at the respective intersections of the data signal lines and the scanning signal lines, each of the pixel sections receiving as a pixel value a voltage applied to the data signal line that passes through the corresponding intersection when the scanning signal line that passes through the corresponding intersection is selected, wherein

a non-image signal is applied to the data signal lines at a boundary point between adjacent horizontal scanning periods, the non-image signal being identical in voltage polarity with an image signal applied in the latter horizontal scanning period of the adjacent horizontal scanning periods.

66. A liquid crystal display device in which a driving method according to claim 65 is employed.